Indicators define the metrics you can query and are categorized into Custom Indicators and UTM Indicators.
Custom indicators are valid for custom dimensions:
pv,uv,add_cart_uv, add_cart_qty,add_payment_info_uv,begin_checkout_pv,
begin_checkout_uv,orders, sales,conversion_rate
UTM indicators are valid for UTM dimensions
pv,uv,add_cart_uv,begin_checkout_pv,
begin_checkout_uv,orders, sales